BIO-CRUDE PRODUCTION VIA HYDROTHERMAL LIQUEFACTION OF ENTEROMORPHA PROLIFERA: OPERATING CONDITION OPTIMIZATION AND HIGH-RESOLUTION FT-ICR MASS SPECTRAL ANALYSIS

Enteromorpha prolifera is one of the main species causing green tide. In this study, hydrothermal liquefaction of E. prolifera was carried out, and the operating conditions were optimized using response surface methodology. The results indicated that hydrothermal liquefaction at 295 degrees C with 14% solids content produced the highest bio-oil yield of 18.4%. The higher heating value was 31.9 to 34.2 MJ kg(-1) and almost monotonically increased with increasing reaction temperature. The energy recovery, carbon recovery, and nitrogen recovery of bio-crude were mainly dependent on yield rather than elemental composition as the investigated variables changed. The chemical composition of bio-crude was characterized by Fourier transform ion cyclotron resonance mass spectrometry. The acidic O-containing compounds were mainly O-2 class compounds, namely hexadecanoic acid and octadecanoic acid. The basic N-containing compounds were mainly nitrogenous heterocyclic compounds with carbon numbers of 20 to 40 and high degrees of unsaturation.